Consumer electronics devices are continually getting smaller and, with advances in technology, are gaining ever increasing performance and functionality. This is clearly evident in the technology used in consumer electronic products such as mobile phones, laptop computers, MP3 players and personal digital assistants (PDAs). Requirements of the mobile phone industry for example, are driving the components to become smaller with higher functionality and reduced cost. It is therefore desirable to integrate functions of electronic circuits together and combine them with transducer devices such as microphones and speakers.
The result of this is the emergence of micro-electrical-mechanical-systems (MEMS) based transducer devices. These may be for example, capacitive transducers for detecting and/or generating pressure/sound waves or transducers for detecting acceleration. There is a continual drive to reduce the size and cost of these devices through integration with the electronic circuitry necessary to operate and process the information from the MEMS through the removal of the transducer-electronic interfaces. One of the challenges in reaching these goals is the difficulty of achieving compatibility with standard processes used to fabricate complementary-metal-oxide-semiconductor (CMOS) electronic devices during manufacture of MEMS devices. This is required to allow integration of MEMS devices directly with conventional electronics using the same materials and processing machinery. This invention seeks to address this area.